Messages in this thread Patch in this message |  | | | Date | Tue, 21 Jun 2011 15:16:15 GMT | | From | "tip-bot for " <> | | Subject | [tip:x86/uv] x86, UV: Fix smp_processor_id() use in a preemptable region |
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Commit-ID: 00b30cf04a775b5292ab704f782394e36e25617d Gitweb: http://git.kernel.org/tip/00b30cf04a775b5292ab704f782394e36e25617d Author: cpw@sgi.com <cpw@sgi.com> AuthorDate: Tue, 21 Jun 2011 07:21:26 -0500 Committer: Ingo Molnar <mingo@elte.hu> CommitDate: Tue, 21 Jun 2011 14:50:31 +0200
x86, UV: Fix smp_processor_id() use in a preemptable region
Fix a call by tunables_write() to smp_processor_id() within a preemptable region.
Call get_cpu()/put_cpu() around the region where the returned cpu number is actually used, which makes it non-preemptable.
A DEBUG_PREEMPT warning is prevented.
UV does not support cpu hotplug yet, but this is a step toward that ability as well.
Signed-off-by: Cliff Wickman <cpw@sgi.com> Link: http://lkml.kernel.org/r/20110621122242.086384966@sgi.com Signed-off-by: Ingo Molnar <mingo@elte.hu> --- arch/x86/platform/uv/tlb_uv.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c index 68e467f..34be650 100644 --- a/arch/x86/platform/uv/tlb_uv.c +++ b/arch/x86/platform/uv/tlb_uv.c @@ -1334,9 +1334,10 @@ static ssize_t tunables_write(struct file *file, const char __user *user, instr[count] = '\0'; - bcp = &per_cpu(bau_control, smp_processor_id()); - + cpu = get_cpu(); + bcp = &per_cpu(bau_control, cpu); ret = parse_tunables_write(bcp, instr, count); + put_cpu(); if (ret) return ret;
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